“You will be able to browse into the sky like never before,” said Carol Christian, an astronomer with the Space Telescope Science Institute, a nonprofit academic consortium that supports the Hubble Space Telescope. “These are really the images of the sky. Everything is real.”

The Sky imagery was stitched together from more than one million photographs from scientific and academic sources, including the Sloan Digital Sky Survey, the Palomar Observatory at the California Institute of Technology and the NASA-financed Hubble.

Microsoft has a research project called the World Wide Telescope that offers similar capabilities to Sky. The project was once headed by Jim Gray, the veteran Microsoft researcher who disappeared this year after a sailing trip off San Francisco Bay.